APPENDIX N 

MOHAVE GROUND SQUIRREL HABITAT 

ASSESSMENT 

Mohave Ground Squirrel Habitat Assessment 

DesertXpress Rail Project 

Prepared for 

Jones & Stokes 

2600 V Street 

Sacramento, CA 95829 

Prepared by 

Philip Leitner 

2 Parkway Court 

Orinda, CA 94563 

November 16, 2007 
INTRODUCTION 

The DesertXpress Rail Project is proposed to provide high speed passenger 

service between Victorville, California and Las Vegas, Nevada. Between Victorville and 

Barstow, two possible alignments are being evaluated. The Segment 1A alignment 

would follow the existing Mojave Northern Rail right-of-way that runs along the east side 

of the Mojave River. The Segment 1B alignment would follow the I-15 highway route 

from just north of Victorville to the Hodge Road Interchange and then strike north 

through open land to join the Alternative A route just south of Barstow. A single route is 

proposed through Barstow, crossing to the north side of the Mojave River near Lenwood 

and proceeding eastward to join the I-15 highway right-of-way where it is intersected by 

Old Highway 58. Two alternate alignments are being considered in the vicinity of 

Yermo. One route (Segment 2B) would run along the north side of I-15 from the 

interchange with Ft. Irwin Road east to the Agricultural Inspection Station. The other 

route (Segment 2A) would also be parallel to I-15, but about 0.75 mi to the north of the 

highway. 

The permitting process for this project includes documentation of biological 

resources that may exist along the alternative alignments. As part of this effort, I 

conducted a field survey in May 2007 to assess the suitability of the proposed alignments 

between Victorville and Yermo as potential habitat for the Mohave ground squirrel 

(Spermophilus mohavensis), a species listed as Threatened by the State of California. In 

much of this region, the geographic range of the species is considered to lie west of the 

Mojave River. However, in the Victorville and Barstow areas, there are records of 

Mohave ground squirrel occurrence on the east side of the Mojave River. 

The currently-accepted range boundary and all occurrence records within 10 miles 

of the boundary are shown on Fig. 1. Appendix A lists all Mohave ground squirrel 

occurrence records plotted on Fig. 1, along with information on the date of the detection 

and number of animals reported. Although the alternative DesertXpress alignments 

between Victorville and Barstow are generally outside of the currently-accepted range 

boundary, the Mohave Ground Squirrel Survey Guidelines (California Department of 

Fish and Game, 2003) define potential habitat as land supporting desert scrub vegetation 

within or adjacent to the geographic range of the species. The Guidelines indicate that 

trapping surveys to establish presence or absence of the Mohave ground squirrel may be 

required for projects located within 5 miles of the current range boundary. As shown in 

Fig. 1, the alternative routes for the DesertXpress project are almost entirely within the 5 

mile zone. Because of this, it was considered necessary to conduct habitat suitability 

surveys along these routes for the Mohave ground squirrel. This report describes the 

habitat assessment methodology used, evaluates the habitat suitability of all alignments 

between Victorville and Yermo, and presents recommendations for presence/absence 

surveys. 

HABITAT ASSESSMENT METHODS 

Habitat suitability along the proposed DesertXpress alignments was evaluated by 

surveying all routes between Victorville and Yermo by automobile and on foot. Habitat 

assessment efforts were focused on a 300 ft corridor that included the centerline of the 

right-of-way (ROW) and the adjoining habitat. This corridor was examined visually and 

detailed notes were taken on habitat characteristics such as land use, topography, soils, 

and vegetation. In addition, the habitat characteristics of nearby areas that showed 

connectivity with the corridor were carefully noted. A total of 54 hours was spent in the 

field during the period 25-30 May 2007. Other research in support of this assessment 

included checking the results of trapping surveys conducted previously in this region and 

preparing a database of all records of Mohave ground squirrel occurrence within 10 miles 

of the eastern edge of the species geographic range between Victorville and Yermo. 

RESULTS 

As the alignments were surveyed, they were divided into linear sections that were 

characterized by similar land use, topography, soil conditions, and vegetation. Each 

section was given a numerical designation from 1 through 35 (Fig. 2). Table 1 lists these 

sections in numerical order. Sections 1, 2, and 2A are at the Victorville terminus of the 

proposed railroad line in an area that could be developed for a station and parking 

facility. Sections 3 through 12 are located on the Segment 1A alignment that runs from 

the Victorville terminus along the Mojave River toward Barstow, while Sections 13-20 

are on the Segment 1B alignment starting at the Victorville terminus and ending where 

the 2 routes join southwest of Barstow. Sections 21 through 28 are located along the 

single route that swings to the north of the Mojave River and runs eastward through the 

Barstow area. Finally, Sections 29-31 are on the Segment 2B alignment that runs along 

the north side of I-15 from Fort Irwin Road to the Agricultural Inspection Station just east 

of Yermo, while Sections 32-35 are on the Segment 2A alignment about 0.75 mile to the 

north. 

Seventeen sections of ROW were judged to be unsuitable as Mohave ground 

squirrel habitat (Table 1). There were several reasons for considering a particular section 

to be unsuitable. Some were characterized by steep, rocky terrain with no alluvial soils 

suitable for burrow construction. In other cases, the land surface was severely disturbed 

and supported little or no native vegetation. One section (No. 33) traversed a dry lake 

bed (playa) where the salty soil prevented vegetative growth. Finally, the land in several 

sections had been converted to agricultural, commercial, or residential uses. 

The 20 sections of ROW that were classified as suitable habitat were on flat to 

moderately-sloping terrain with alluvial soils and all supported native desert scrub 

vegetation (Table 1). Twelve of these sections were in habitat classified as Mojave 

Creosote Bush Scrub, while 3 other sections were in Desert Saltbush Scrub communities. 

The remaining 5 sections included both types of habitat. Both Mojave Creosote Bush 

Scrub and Desert Saltbush Scrub are known to provide habitat for the Mohave ground 

squirrel (Gustafson, 1993). 


 
Table 1. Assessment of habitat suitability for the Mohave ground squirrel along the 

DesertXpress alignments between Victorville and Yermo. Code designations for 

important shrub species include ATPO (allscale saltbush) and LATR (creosote bush). 

Section 

Number Dimensions Habitat Suitability Habitat Description 

1 ~60acres Suitable LATR scrub / low diversity 

2 ~65 acres Suitable LATR scrub / low diversity 

2A ~20 acres Unsuitable Barren 

3 ~60 acres Suitable LATR / ATPO in wash with LATR scrub in upland to W 

4 ~90 acres Suitable LATR scrub / medium diversity in small washes 

5 1.9 mi Unsuitable LATR scrub / low diversity / very rocky granitic hills 

6 11.8 mi Unsuitable Operational & abandoned ag fields / rural homes & ranches 

7 1.6 mi Unsuitable Steep rocky hills meet riparian vegetation zone 

8 1.7 mi Suitable ATPO in small washes / LATR on interfluves 

9 1.6 mi Unsuitable Agricultural land uses / cropland & dairies 

10 4.6 mi Suitable Monotypic ATPO stands / some areas sparse, low cover 

11 2.0 mi Unsuitable Operational & abandoned ag fields / rural homes & ranches 

12 1.3 mi Suitable Saltbush scrub / some shrub diversity including LATR 

13 ~90 acres Suitable LATR scrub / low diversity 

13A ~30 acres Unsuitable Commercial development / almost no perennial vegetation 

14 ~220 acres Suitable LATR scrub / low diversity / steep ravines 

15 4.2 mi Suitable LATR scrub / low diversity / gently-sloping bajada 

16 4.3 mi Suitable LATR scrub / low diversity / rocky hills & bajadas 

17 4.4 mi Suitable LATR scrub / low diversity / bajada sloping to W 

18 1.0 mi Unsuitable Disturbed & barren / very sparse shrub cover 

19 5.3 mi Suitable LATR scrub / low diversity / flats, washes, low hills 

20 2.1 mi Suitable LATR scrub / medium diversity 

21 0.9 mi Suitable Saltbush scrub with sand dunes 

22 2.0 mi Unsuitable Mostly dunes with little native vegetation / abandoned fields 

23 1.7 mi Unsuitable Disturbed ag land & dunes / little native vegetation 

24 0.9 mi Suitable Dense saltbush scrub along abandoned RR embankment 

25 2.5 mi Unsuitable Occasional saltbush / vegetation very sparse 

26 3.1 mi Unsuitable Occasional saltbush / disturbed & barren land 

27 1.4 mi Suitable Saltbush scrub in wash / LATR scrub low diversity in upland 

28 2.6 mi Unsuitable Rocky steep terrain / almost no perennial vegetation 

29 2.3 mi Unsuitable Very low density LATR patches / scattered development 

30 2.0 mi Suitable LATR scrub / low diversity 

31 4.0 mi Unsuitable Very sparse shrub cover / artificial drainage channel / rocky 

32 2.2 mi Suitable LATR scrub grading into saltbush scrub / very sparse 

33 2.2 mi Unsuitable Barren playa 

34 1.7 mi Suitable LATR scrub / low diversity / on bajada slope 

35 1.2 mi Unsuitable LATR scrub / low diversity / rocky bajada / very sparse 
DISCUSSION 

DesertXpress Alignments in Relation to Mohave Ground Squirrel Distribution 

The propos

 the currentl

ed press alignments from V enerally 

w y undary of the Mohav raphic range 

Figure are r o currences close to the 

ropos t 1A th delanto. Although some 

 thes re e been 2 occurrences in the last 3 years (CNDDB 

cc. # 9). n

ojav t t everal 

ccurren e v a 

ropose ex 

ccepte oun

lose to ose e most 

ecent re ccu and ~8 

i from ose

ere are hav i

iles of ent a

temp ea. 

hav q t

M grou l h

rrow tion ety

equat d m ou ons 

 Dese RO habitat are 

aracte allu an

pport grou el ear that abundant, high 

ality f sour ail press alignments. 

udies ou

nata) y h te 

 the ac son w n h

sentia ear

 grou els

rbace ies, i cot 

allow alce

anthu thus kw composites such as 

oreops The

emme (Er a

arrea ta), and cactus (O

nduct the e areas 

here a riet a

ere no s be 

 DesertX

-accepted bo

ictorville to Yermo g

follo e ground squirrel geog

( 1). There a numbe f Mohave ground squirrel oc

p ed Segmen route in e vicinity of Victorville and A

of e records a quite old, th re have 

O 325 and 32 There is a older record (1977) near Helendale just across the 

M e River from he Segmen 1A route (CNDDB Occ. #18). Finally, there are s

o ces in th icinity of Barstow, including a visual observation on July 8, 2005 at

p d landfill

d

pansion site ~4 miles south of Barstow, well beyond the currentlya range b dary (Simon are very 

d r

, 2006). Two of the records in the Barstow area 

c the prop DesertXp ss alignment (CNDDB Occ. #276 and 277. The

r ported o rrence (May ow

d pr

 2007) was at a site near SR 58 west of Barst

m the prop DesertX ess route (ECORP Consulting, unpubl. data). Although 

th no Mo e ground squ

ly r

rrel records near the Segment 1B route, it is within a few 

m the curr -accepted nge boundary and there have been few trapping 

at ts in this ar

Mo e Ground S uirrel Habita Suitability 

ohave nd squirre abitat requirements include alluvial soils suitable for

bu construc and a vari of shrubs and herbaceous plants sufficient to supply

ad e food an oisture thr gh the active season (February-July). The 20 secti

of rtXpress W that were identified as suitable Mohave ground squirrel 

ch rized by vial soils d the presence of plant communities that are known to

su Mohave nd squirr populations. However, it is not cl

qu orage re ces are av able in the vicinity of the DesertX

St in Inyo C nty have shown that the foliage of winterfat (Krascheninnikovia 

la and spin opsage (Grayia spinosa) are important in the diet both early and la

in tive sea hen gree erbaceous plants are not available and they appear to be 

es l in dry y s (Leitner and Leitner, 1998). 

Mohave nd squirr also feed on the foliage and seeds of a number of native 

he ous spec including m lkvetch (Astragalus spp.), lupines (Lupinus spp.), apri

m (Sphaer a ambigua), white mallow (Eremalche exilis), gilia (Gilia spp.), 

lin s (Linan spp.), buc heat (Eriogonum spp.), and 

C is spp. only non-na

o t

tive herb that can appear to any extent in the diet is redst d filaree dium cicu rum). Seeds of boxthorn (Lycium spp.), creosote bush 

(L tridenta puntia spp.) can be important as well. The survey 

co ed along D proposed sertXpress routes in May did not detect many 

w good va

t obviou

y of these pl

cause of the

nts occur. It is possible that the herbaceous species 

w extremely dry winter. Although the 20 sections 
identified as suitable do not appear to provide high quality habitat, there is the potential 

r the presence of the species at any of these locations. 

ONCLUSIONS AND RECOMMENDATIONS 

 upon, 

sis for mitigation of project impacts as required during NEPA 

nalysis and would support the preparation of the Environmental Impact Statement (EIS). 

The second option available to the project proponent is to conduct visual and livetrappin

 plan 

t protocol surveys at the appropriate 

time. If the results of the surveys were negative in some or all of the 20 sections, the 

compen

hat 

r largescale projects, defined as those projects that may impact >180 acres or those linear 

fo

C

A total of 20 linear sections along the various DesertXpress alignments between 

Victorville and Barstow appear to provide suitable Mohave ground squirrel habitat. 

Although habitat quality is not high, it is possible that Mohave ground squirrels could 

occur in these areas. 

One option that is available to the project proponent is to assume the presence of 

the species in those sections of the project alignment that have been identified as suitable 

habitat (California Department of Fish and Game, 2003). The project proponent would

then apply for a California Endangered Species Act incidental-take permit (Fish and 

Game Code Section 2081b) requiring mitigation and compensation. Compensation 

generally involves the purchase of habitat that is known to support the species, payment 

of a fee that will cover future management of the land, and the dedication of that land in 

perpetuity for conservation purposes. The total area that will be impacted must be 

calculated accurately and a compensation ratio determined. If this option is agreed

it could provide the ba

a

g surveys on each of the 20 sections of the project alignment that appear to 

support habitat suitable for the Mohave ground squirrel. 

The option of conducting protocol surveys to determine presence or absence of 

the Mohave ground squirrel would require careful timing. Since the results of these 

surveys are only good for 1 year, they would have to be scheduled within 12 months of 

the time that project construction and ground disturbance are initiated. Because the 

details of the construction schedule are unknown at this point, it would be difficult to

and schedule protocol surveys. A possible strategy would be to assume presence of the 

species in the 20 sections of the ROW with suitable habitat when discussing mitigation of 

impacts in the EIS preparation, but to then carry ou

sation requirements would be reduced or eliminated. Another possible strategy 

would be to propose in the EIS that protocol surveys be conducted within 1 year prior to 

ground disturbance and that compensation would be provided if the surveys indicate t

the species is present in particular sections of the ROW. 

These surveys would follow the guidelines promulgated by the California 

Department of Fish and Game (California Department of Fish and Game, 2003). 

Trapping grids normally consist of 100 traps arranged in a 4 x 25 array for each linear

mile of potential habitat or in a 10 x 10 array for each parcel of 80 acres or less. 

However, the guidelines state that special survey protocols should be developed fo
projects that are >5 miles in length. The Department requires that such special survey 

protocols be developed through its consultation with either the project proponent or the 

cal lead agency (if appropriate) or both entities. The DesertXpress project would 

tocol would have to be designed. 

round squirrel habitat that might be impacted includes a total of 

~585 acres in 6 parcels as well as 37 miles of linear ROW. The 6 parcels are areas that 

could p

r 2.2 

suitable habitat along the DesertXpress alignments between Victorville and Barstow. It 

can be 

 in the amount of sampling 

required on Segments 2A and 2B. 

lo

clearly be considered as large-scale and a special pro

The special sampling protocol could include the following elements. Table 2 

identifies the 20 sections of the ROW on which protocol surveys would be recommended, 

along with the suggested number of trapping grids for each section. It can be seen that

the potential Mohave g

otentially be used for station facilities or construction laydown sites. It is 

recommended that a single grid of 100 traps be used to survey each of these 6 parcels. 

Although Section 14 is >80 acres, only 1 grid is proposed because of marginal habitat 

quality. The recommendations for the 14 sections of linear habitat are generally for 

somewhat <1 grid per mile. The ratios range from 1 grid per 0.9 mile up to 1 grid pe

miles. In all cases where it is proposed that 1 grid should be used to sample >1 mile of 

corridor, the rationale is that habitat in that section is of relatively low quality and 

uniform in character. The exact locations of trapping grids have not been selected, 

pending decisions concerning the final structure of the sampling program. 

A total of 27 trapping grids are recommended in order to adequately survey 

seen that there is much more suitable habitat on Segment 1B than Segment 1A, 

resulting in 12 trapping grids as compared to only 7 grids on Segment 1A along the

Mojave River. On the other hand, there is little difference

 
Table 2. Recommendations for presence/absence trapping surveys for the Mohave 

ground squirrel along the DesertXpress alignments between Victorville and Yermo. 

Code designations for important shrub species include ATPO (allscale saltbush) and

LATR (creosote bush). 

Sec

Nu

ended 

tion 

mber Dimensions Habitat Description 

Recomm

Number of 

Trapping 

Grids

Segment 1 

Common to both alternatives 

1 ~60acres LATR scrub / low diversity 1 

2 ~65 acres LATR scrub / low diversity 1 

Alternative A 

3 ~60 acres LATR / ATPO in wash with LATR scrub in upland to W 1 

4 ~90 acres LATR scrub / medium diversity in small washes 1 

8 1.7 mi ATPO in small washes / LATR on interfluves 1 

10 4.6 mi Monotypic ATPO stands / some areas sparse, low cover 3 

12 1.3 mi Saltbush scrub / some shrub diversity including LATR 1 

Total Grids Segment 1A = 9

Alternative B 

13 ~90 acres LATR scrub / low diversity 1 

14 ~220 acres LATR scrub / low diversity / steep ravines 1 

15 4.2 mi LATR scrub / low diversity / gently-sloping bajada 2 

16 4.3 mi LATR scrub / low diversity / rocky hills & bajadas 2 

17 4.4 mi LATR scrub / low diversity / bajada sloping to W 2 

19 .3 mi LATR scrub / low diversity / flats, washes, low hills 5 3 

20 2.1 mi LATR scrub / medium diversity 1 

Total Grids Segment 1B = 14

Segment 2 

Common to both alternatives 

21 0.9 mi Saltbush scrub with sand dunes 1 

24 0.9 mi Dense saltbush scrub along old RR embankment 1 

27 1.4 mi Saltbush scrub in wash / LATR scrub low diversity in upland 1 

Alternative A 

32 2.2 mi LATR scrub grading into saltbush scrub / very sparse 1 

34 1.7 mi LATR scrub / low diversity / on bajada slope 1 

Total Grids Segment 2A = 5

Alternative B 

30 2.0 mi LATR scrub / low diversity 1 

Total Grids Segment 2 B = 4
REFERENCES 

California Department of Fish and Game. 2003. California Department of Fish and 

Game Mohave Ground Squirrel Survey Guidelines. 5 pp. 

fson, J.R. 1993. A status review of the Mohave ground squirrel (Spermo

 

Gusta philus 

mohavensis). Calif. Dep. Fish and Game, Nongame Bird and Mammal Sect., 

Sacramento, CA. 104 pp. + appendices. 

Leitner, P. and B.M. Leitner. 1998. Coso Grazing Exclosure Monitoring Study. 

 Study, Coso Known Geothermal Resource Area, Major 

ding 9 ppend. 

 2006. Biological Resources Assessment for the Barstow Sanitary Landfill 

pose on ORP 

nsult e

Mohave Ground Squirrel

Fin s, 1988-19 6. Final Report. 42 pp + a

Simon, K. 

Pro d Expansi , San Bernardino County, California. Prepared for EC

Co ing, Inc., R dlands, CA. 26 pp. 
APPENDIX A 

WITHIN 10 MILES OF THE RANGE BOUNDARY 

UTM Coordinates 

(NAD83) 

MOHAVE GROUND SQUIRREL 

OCCURRENCES BETWEEN VICTORVILLE AND YERMO 

CNDDB Occurrence Date Number 

of MGS Easting Northing 

6 6/24/1977 0505471 3872486 1 

12 6/28/1977 0473294 3825889 1 

18 May-June 1977 0468993 3846840 16 

22 5/24/1920 0469096 3828327 1 

40 6/21/1988 0474553 3864762 1 

47 3/02/1919 0472100 3821656 1 

57 1981 0515485 3856715 22 

93 6/19/1988 0455697 3849028 1 

220 5/15/1991 0456186 3840518 2 

258 6/14/1987 0465249 3831769 1 

276 1982 0497530 3863732 1 

277 Mar-Apr 1990 0489309 3862757 Unknown 

283 6/03/1980 0469261 3824931 2 

288 8/17/1993 0499622 3861033 1 

289 8/17/1993 0499762 3860598 1 

290 8/17/1993 0496093 3860328 1 

306 6/24/1977 0506777 3873170 1 

311 5/20/1994 0458853 3853292 1 

325 4/21/2004 0460910 3831816 1 

 7/08/2005 0499076 3853661 1 

329 4/24/2007 0466134 3831302 1 

 May 2007 0475616 3864258 1